刚体极限平衡法与有限元法在工程边坡稳定性分析中的应用与比较

刚体极限平衡法、有限元法在工程边坡稳定分析中是两个常用的计算方法,文中对两种方法的理论基础和计算过程进行了简要介绍,并应用两种方法对一工程实例进行了分析。结果表明,二者的计算结果相近,且相同工况下有限元计算安全系数略小于刚体极限平衡法计算安全系数。     

Drying of Chestnuts (Castanea sativa Mill.) after Osmotic Dehydration with Sucrose and Glucose Solutions

Chestnuts were dehydrated by using a combined method of osmotic dehydration followed by air drying. Samples were osmotically pretreated with sucrose (60% w/w) and glucose (56% w/w) for 8 h, air-dried at temperatures of 45, 55, and 65°C, at a relative humidity of 30% and at a velocity of 2.7 m·s^-1 and the experimental data of the drying kinetics were obtained. Whole samples were dried with different peelings: (a) removal of endocarp and pericarp (peeled) and (b) additionally the internal rough surface (cut). In all cases, cut chestnuts show greater drying rates than peeled samples, indicating that a significant mass transfer resistance in the layer nearest to the surface takes place. Peeled samples pretreated with sucrose solutions behave in a similar way to untreated samples. For the rest of the samples, the cut samples osmotically treated with sucrose solutions and all the samples treated with the glucose solution, the drying rates decrease during drying. Drying kinetics are successfully modeled by employing a diffusional model that takes the shrinkage into account. The effective coefficient of water diffusion was evaluated and correlated with temperature. The quality of the final product was monitored by color change. In spite of the fact that the total color difference is not modified by the osmotic treatment, the L*, a*, and b* color coordinates of cut samples treated with sucrose and glucose solutions do undergo changes; the L* and a* coordinates change less than the b*.     

加强和改进纪检监察工作的几点做法

加强和改进纪检监察工作，必须强化教育，落实党风廉政建设责任制；完善制度，建立有效的监督制约机制：正风肃纪，严肃查处违纪违法案件；围绕中心，开展效能监察工作；维护稳定，构建企业和谐稳定环境。     

Correlation study between standard plate count and flow cytometry for determination of raw milk total bacterial count

Milk samples were collected in the dry season ( n =  155) and in the rainy season ( n =  68) to establish a correlation between electronic flow cytometry and standard plate count for the determination of total bacterial count of raw milk. Results were expressed in individual bacterial count (ibc) and colony forming unit (cfu) for electronic flow cytometry (Bactocount) and standard plate count, respectively. The accuracy of Bactocount, denoted by the residual standard deviation ( s ( y,x )), was 0.309 log cfu/mL. The predictive interval of estimated values was broad and it is suggested that total bacterial count should be expressed in ibc without transformation to cfu.     

FS-DDDP方法及其在水库群优化调度中的应用

可行搜索-离散微分动态规划(FS-DDDP)方法是在考虑水库运行的综合利用要求的前提下,利用正向搜索和逆向搜索相结合的方式寻找水库优化调度过程的大量可行轨迹,以目标函数较大的几个可行轨迹作为DDDP方法的初始轨迹分别进行再寻优计算的优化算法.该方法可进行单库优化计算,也可进行库群优化计算.黄河上游梯级水库数量较多,综合利用要求复杂.文中以该梯级为例,说明FS-DDDP方法可在满足该梯级水库群的河流生态用水、防凌用水、灌溉用水、发电用水等综合利用要求的前提下,以水库群发电效益最大为目标,求得水库群优化调度的较好解.     

流域非点源污染源解析的投影寻踪对应分析方法

为分析非点源污染物及其来源的因果关系,提出了基于加速遗传算法的投影寻踪对应分析方法(PP-CFA),并应用于流域非点源污染源解析研究中。应用结果表明:土地利用方式与流域营养物地表径流输入特征之间存在明显的3类对应关系;巢湖各主要入湖河流水中N和P营养盐分输入特征可以分为差异明显的3类;改进土地利用方式和有效控制营养盐分的输入,是减少和控制巢湖流域非点源污染的重要途径。由于PP-CFA根据一维投影值的散布图进行聚类分析,因而操作较现有方法简便,精度亦容易保证。     

斜向波与长棱柱型浮式结构物相互作用的边界元模拟

采用第二类变形Bessel函数对斜向线性入射波与任意截面形状的长棱柱型浮式海洋结构物的相互作用问题进行了边界元法模拟,给出了常数元和线性元的奇异积分处理方法以及开边界的处理方式。对矩形和圆形结构物的水动力系数和波浪力进行了计算,并与解析解及有限元计算结果进行了比较。结果表明,本文方法能得到满意的结果,且未出现不规则频率现象。     

高空核爆炸瞬发中子在大气中产生的电离源

本文计算并分析了在高空核爆条件下瞬发中子在大气中产生的电离源。计算结果表明,在离开地球表面高度Z=30km处,当t≈1ms时,电离源强度Ne≈10~(12)s~(-1)·cm~(-3)。峰值维持时间为0.4—4ms。并给出了对Z>30km以上各高度Ne随t的变化曲线。     

基于ANSYS的闩体刚强度有限元分析

闩体的刚度和强度必须满足设计要求。用有限元法对复杂结构件进行力学性能分析是非常有效的方法。采用ANSYS软件对闩体进行了刚度和强度分析,得出了有用的结论,可供相关设计借鉴。     

碳热还原法制备耐火材料用AlN的研究

AlN在很多方面具有优异的性能,它在耐火材料中的应用日益引起人们的关注.但是,由于高纯AlN价格昂贵,限制了它在耐火材料领域的使用.本文采用碳热还原法研究了不同反应温度、反应时间、铝源及原料粒度对AlN制备结果的影响.结果表明,以400目的Al(OH)3在1500℃下,反应5h,即可制备出低成本、适合耐火材料用AlN.